Automatic circuit-breaker for motors



A. C. TABBOT.

AUTOMATIC CIRCUIT BREAKER FOR MOTORS.

APPLICATION FILED APR.29, 191B.

1 ,332, 696, Patentd Mar. 2, 1920.

2 SHEETS-SHEET I,

I 3140214 for attormzq A. c. TABBOT.

AUTOMATIC CIRCUIT BREAKER FOR MOTORS.

APPLiCATlON FILED APR.29. 1918.

Patented Mar. 2,1920.

I gmmm v I r I" OF ATLANTA, GEORGIA.

ARTHUR C. TAIBBOT,

FIE.

AUTOMATIC CIRCUIT-BREAKER FOR MOTORS.

Specification of Letters Patent.

Patented Mar. 2, 1920.

Application filed April 29, 1918. Serial N 0. 231,383.

useful Improvements in Automatic Circuit- Breakers for Motors, of which the following a specification.

This invention relates to improvements in safety attachments for motors, and the principal object of the invention is to provide an automatic circuit breaker for use in connection with the armature shaft bearings of A. C. and D. C. motors whereby when said bearings become worn to a predetermined degree, the circuit breakers will be closed and will act upon the usual starting rheostat in a manner to denergiz'e the same whereby to cause the starting or control lever to instantly move to its off position, thus, interrupting the flow of current to the motor and therefore stopping the same.

Another and equally important object of the invention is to provide an adjustable circuit breaker which can be regulated to cause the functioning of the same at predetermined periods in order that the motor will be stopped thereby. V

In order that the invention and the manner of its application may be readily understood by those skilled in the art, I have in the accompanying illustrative drawings and in the detailed following description based thereon set forth a preferred embodiment of the invention.

In the drawings:

Figure 1 is a vertical fragmentary section through a portion of a motor housing showing the improved circuit breaking means applied to one bearing thereof,

Fig. 2 is a section taken on the line 2-2 I i of Fig. 1,

Fig 3 is a similar view taken on the line s 3 of Fig. 1,

Fig. 4 is a fragmentary detail through the housing of the circuit breaker showing the arrangement of the spring contact element, and

Fig. 5 is a diagrammatic view showing the method of arranging the wiring between the circuit breaker and the starting rheostat of a motor.

Having more particular reference to the drawings, in connection with which like reference characters will designate corresponding parts throughout the several views, 1

represents a fragment of a motor housing, the same being provided with a bearing 2 for receiving one end of the armature shaft 3; it being of course understood in'this c011- nection, that two such bearings are provided, one for each extremity of the armature shaft. However, for the purpose of convenience, I have disclosed but one of these hearings, it being understood that the construction and arrangement of the circuit breaker with relation thereto is identical in each instance.

Secured to the inner side of the bearing 2 is an annular housing 41 having a flanged marginal portion which is provided with a plurality of screw threaded openings in order that the closure 5 can be arranged thereover and secured to the same by means of clamp-screws 6 or other similar fastening devices. Horizontally disposed slots are formed in the outer wall of the housing, for a purpose which will be subsequently described.

Arranged in the housing 1 at a point in proximity to the inner marginal portion thereof and insulated therefrom, are a pair of normally spaced spring contact elements 7 said elements being. provided with suitable terminals 8 with which branch conductors 9 are engaged and are extended into engagement with the lead wires of the motor, designated by the numeral 10, it being noted in this connection that said branch conductors 9 are engaged with the lead at points between the starting rheostat 11 and the latter; a relay 12 being interposed in said branch conductors and having the circuit closing element thereof disposed for normal engagement with spaced contacts 13 connected to the lead wires 10 at points between the same and the motor.

Arranged in the housing 4 adjacent the outer wall thereof is an annular plate 14, which as will be noted is provided with r'adially disposed slots 15 adapted to register with suitable apertures in the outer wall of the housing in order that bolts 16 may be passed therethrough and through the slots 15 for connecting the plate 14 to said outer wall, these bolts being provided with wing nuts 17 for an obvious purpose. Engaged with and projecting laterally from the plate 14 are a plurality of circularly disposed guide pins 18 which are adapted to he slidably engaged in apertures in an annular plate 19, the latter having an internally screw threaded central opening as at 20 for a purpose to be hereinafter described. Contractile coil springs 21 are engaged with the plates 14 and 19 and serve to normally maintain the plate 19 in its neutral or disengaged position with respect to the spring contact elements 7.

Secured to the armature shaft 3 is a sleeve 22, one portion of which is screw threaded as at 23, and provided with a threaded aperture to receive a set-screw 24; it being noted that the outer end of the sleeve 22 is disposed at a point adjacent the plate 14.

v In operation, the plate 14: is properly adjusted with relation to the housing 4: by the coaction of the slots 15, bolts 16 and wing nuts 17. In this position, the screw threaded opening of the plate 19 will be in spaced relation to the screw threaded portion 23 of the sleeve 22, and as a consequence rotation of said sleeve by reason of its connection with the armature shaft 3 will in no way effect said plate. However, should the bearing 2 become worn to a predetermined degree, the screw threaded portion 28 of said sleeve 22 will be permitted to engage with the screw threaded portion 20 of the plate 19 and cause said plate to be moved inwardly over the guide pins 18 until it engages the near spring contact element 7, whereupon itwill serve to move said contact element into engagement with the adjacent contact element, thus closing the circuit through the branch conductors 9 and thereby operating the relay 12 to cause the breaking of the circuit through the starting rheostat, which upon being deenergized will permit the starting or control lever thereof to be instantly -moved to its off or neutral position and as a consequence stop the motor. Thus, it will be seen that any injury to the windings of the motor which would be otherwise caused by the rapidly rotating armature will be eliminated and as a consequence, a material saving to the user effected.

It may be here noted that my improved circuit breaker may be adapted for use upon various types of motors, such as conditions or preference may dictate, and should it become necessary, may be positioned at any desirable point with relation to the bearings of the motor receiving the same in order to insure proper functioning thereof.

As above. indicated, I do not wish to be understood as confining the invention to the particular embodiment chosen for illustration herein, nor to the exact construction, arrangement and adaptation of parts shown and described, but I reserve the right to make any changes and alterations that fairly fall within the spirit and scope of the invention.

I claim:

1. In an apparatus of the class described a shaft, a supporting bearing for the shaft,

a housing attached to the bearing, a threaded sleeve attached to the shaft, a plate adjustably coupled to the housing and provided with a plurality of guide pins, a plate slidable on said pins and having a threaded opening adapted to be engaged with the threaded sleeve by change of position of the shaft, and electrical contacts disposed in face contact by the slidable plate when moved under the influence of the threaded sleeve.

2. In a device of the class described a revolving shaft, a stationary member, a sleeve rotatable with the shaft, a member adjustable relatively to. the stationary member, a member slidable relatively to the adjustable member and adapted to be coupled to the sleeve for movement away from the adjustable member, and electrical contacts normally spaced and adapted to be closed by the slidable plate under the influence of the sleeve.

3. In a device of the class described a revolving shaft, a member stationary relatively to the shaft, a sleeve rotated with the shaft, a movable member having an opening engaging over the sleeve and adapted to engage with the sleeve by change of location thereof, means for slidably coupling said movable member relatively to the stationary member, and electrical contacts in spaced re lation, said contacts adapted to be disposed in face contact by the slidable plate when moved under the influence of the sleeve.

4. In a device of the class described, a revolving shaft, a member stationary relatively to the shaft, a sleeve rotated with the shaft, a movable member having an opening engaging over the sleeve and adapted to engage with the sleeve by the change of location thereof, means for slidably coupling said movable member relatively to the stationary member, electrical contacts in spaced relation, a rheostat and a relay connected in circuit with the contacts, said contacts adapted to be disposed in face contact by the slidable plate when moved under the influence of the sleeve to close the circuit through the rheostat and dispose the same in neutral position.

In testimony whereof, I affix my signature hereto.

ARTHUR C. TABBOT. 

